Disposable absorbent articles may be used by infants, toddlers, and incontinent individuals to receive and contain body exudates. Some disposable absorbent articles may provide an indicator feature, such as a wetness indicator. A wetness indicator can allow a caregiver to know when the wearer has urinated and/or soiled the article. A prompt removal of the wet absorbent article may help prevent a number of skin or health issues that may result from or be exacerbated by prolonged exposure of the skin to moisture.
Many wetness indicators are binary. That is, the wetness indicator may be one color when dry and then triggered to become another color by any wetness in the article, even with a very small amount. This may be sufficient and even good for small children who have sensitive skin or need to be carefully monitored to insure they are fully hydrated. For larger children, an absorbent article may contain some wetness and yet not urgently need to be changed. For such a circumstance, a wetness indicator that has been triggered may not necessarily be very helpful to the caregiver, who might not desire to change the article until several insults have occurred.
In some circumstances, it would be more helpful to the caregiver for an absorbent article to have a volume indicator, that is, some indication that the article has reached a certain load. Some volume indicators may be location-based wetness indicators. For example, as multiple insults occur, the wetness may be forced to travel further from its original source, and once a particular location indicates wetness, the caregiver may know that a certain volume has been released into the article. The problem with some location-based volume indicators is that their accuracy may not be reliable, as they can be dependent on the positioning of the article on the wearer during insult (sleeping vs sitting vs standing vs crawling). In addition, results may vary according to the gender of the wearer.
These and other difficulties mean that there is a continuing need for volume indicators that can be a reliable gauge of the volume of liquid that the absorbent article is holding, independent of the wearer.